@sjmcc13
Whoa, settle down.
There's a big difference between a saw and a chain saw, and human bone is also quite soft in comparison to stone, let alone the monsters were talking about here, with their bullet-poof skin and scales.
As you stated, the nature of the material is very important when trying to cut or process it. In this case we have a superpowered monsters, this point alone usually makes normal processing methods insufficient. This is also suggested by how resistant the creatures are to any conventional weaponry, if military hardware loses against them, assuming that old style cutting tools will still work seems a stretch.
Yes, they treat the MC very poorly, slave or not. He is a baggage carrier, that's about as lowest level physical labor job as you can get. Yes he gets paid decently, but he's also working in a lethal workplace. The money is for hazard pay, not skill or ability. Add on to this how they treat him, and it's clear they think little to nothing of him. I mean seriously, they essentially left him for dead when he got aggro, and the moment they find the monsters dead, the first action is to pressure him into giving up all rights to kill, he's clearly at the bottom of the totem pole here.
As for the assumption that they would have proper tools, did you forget that they just had baggage carriers pouring ammunition that is clearly described as being completely ineffective all over the monster last chapter? Every single thing about how this group has operated so far has been horribly crude and mostly ineffective, the only functional party member they have is the tank, no one else is shown as accomplishing anything other than getting knocked around. This looks more like a neighborhood operation than any kind of proper group. It was only the absurd level of dumb luck the MC had that they accomplished anything at all.